Copper-gallium target material and method for producing the same

Abstract

The application provides a preparation method of a copper-gallium target material, comprising the following steps: taking high-purity copper blocks and high-purity gallium as raw materials to perform vacuum smelting, the content of gallium in the raw materials is 35-55 wt.%, after the smelting is completed, the copper-gallium alloy is obtained by casting into a mold and cooling; the temperature of the vacuum smelting is 800-900 DEG C; the copper-gallium alloy is sprayed to prepare powder, and the copper-gallium alloy powder is obtained; the copper-gallium alloy powder is subjected to hot isostatic pressing and cooling, and the copper-gallium target material is obtained. The copper-gallium target material with high density and good uniformity of components is prepared by the following steps: first, a high-gallium copper-gallium alloy is prepared by using a vacuum casting method, then, alloy powder is prepared by using a gas spraying method, and finally, the copper-gallium target material is prepared by hot isostatic pressing sintering and annealing.

Description

Technical Field

[0001] This invention relates to the field of materials preparation technology, and more specifically, to a copper-gallium target and its preparation method. Background Technology

[0002] Copper-gallium alloys are the basic materials for CIG (copper indium gallium) and CIGS (copper indium gallium selenide) thin-film solar materials. To facilitate the adjustment and precise control of the elemental composition ratios in CIG and CIGS pre-films and obtain films with high Ga content, copper-gallium alloy targets with high Ga content are required as raw materials. However, for copper-gallium alloys and targets with high Ga content (greater than 35%), the material becomes brittle at higher Ga contents, necessitating improvements in the manufacturing process. Currently, Cu-Ga targets are mainly manufactured using two methods: direct melting (casting) and powder metallurgy. The casting method suffers from component segregation and the inability to eliminate porosity, while the general powder metallurgy method has the disadvantage of low density and susceptibility to cracking. Summary of the Invention

[0003] To address the aforementioned technical problems, this application provides a method for preparing a copper-gallium target.

[0004] To achieve the above objectives, this application proposes the following technical solution:

[0005] In a first aspect, a method for preparing a copper-gallium target is provided, comprising:

[0006] High-purity copper blocks and high-purity gallium are vacuum-melted as raw materials, wherein the gallium content in the raw materials is 35~55 wt.%, and after melting, the mixture is cast into a mold and cooled to obtain a copper-gallium alloy; the temperature of the vacuum melting is 800~900℃.

[0007] Copper-gallium alloy is spray-dried to obtain copper-gallium alloy powder;

[0008] Copper-gallium alloy powder is subjected to hot isostatic pressing and then cooled to obtain copper-gallium target material.

[0009] Preferably, the temperature of the hot isostatic pressing is 600-700℃; the pressure of the hot isostatic pressing is 150-200 MPa; and the heat preservation and pressure holding time of the hot isostatic pressing is 90-120 min.

[0010] Preferably, the vacuum degree of the vacuum melting is <0.2 Pa; and the vacuum melting time is 60-90 min.

[0011] Preferably, the atomization temperature of the spray powder is 1000-1100℃; the atomization pressure of the spray powder is 10-12 bar; and the atomization rate of the spray powder is 1-3 kg / min.

[0012] Preferably, the particle size of the copper-gallium alloy powder is no greater than 60 mesh.

[0013] Preferably, the step also includes annealing the copper-gallium target.

[0014] Preferably, the annealing temperature is 300~400℃; the annealing time is 2~3h.

[0015] Secondly, a copper-gallium target is provided, which is prepared using the aforementioned preparation method.

[0016] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects:

[0017] High-gallium copper-gallium alloys were prepared by vacuum casting, alloy powders were prepared by gas atomization, and high-density copper-gallium targets with good compositional uniformity were further prepared by hot isostatic pressing sintering. Detailed Implementation

[0018] When preparing copper-gallium targets with high gallium content (above 35 wt.%), the applicant found that compared with copper-gallium targets with low gallium content, such targets are prone to material segregation. In response to this phenomenon, the applicant has developed a new method for preparing copper-gallium targets, which can produce copper-gallium targets with high gallium content and good material composition uniformity.

[0019] This invention provides a method for preparing a copper-gallium target, comprising:

[0020] High-purity copper blocks and high-purity gallium are vacuum-melted as raw materials, wherein the gallium content is 35~55 wt.%. After melting, the alloy is cast into a mold and cooled to obtain a copper-gallium alloy. The vacuum melting temperature is 800~900℃.

[0021] Copper-gallium alloy is spray-dried to obtain copper-gallium alloy powder;

[0022] Copper-gallium alloy powder is subjected to hot isostatic pressing and then cooled to obtain copper-gallium target material.

[0023] The vacuum melting temperature is 800~900℃, for example 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, etc.

[0024] It is worth noting that in this preparation method, the casting is completed immediately after melting, and the casting temperature is the same as the vacuum melting temperature, which is 800~900℃, such as 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, etc.

[0025] In some preferred embodiments, the temperature of the hot isostatic pressing is 600-700°C, specifically, it can be 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C, 700°C, etc.

[0026] In some preferred embodiments, the pressure of the hot isostatic pressing is 150-200 MPa, such as 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, etc.

[0027] In some preferred embodiments, the heat holding and pressure holding time of the hot isostatic pressing is 90 to 120 minutes, such as 90 minutes, 95 minutes, 100 minutes, 105 minutes, 110 minutes, 115 minutes, 120 minutes, etc.

[0028] In some preferred embodiments, the vacuum degree of the vacuum melting is <0.2 Pa; the vacuum melting time is 60-90 min, for example 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, etc.

[0029] The gallium content in the high-purity copper block and high-purity gallium raw materials is 35-55 wt%, for example, 35 wt%, 36 wt%, 37 wt%, 38 wt%, 39 wt%, 40 wt%, 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%, 50 wt%, 51 wt%, 52 wt%, 53 wt%, 54 wt%, 55 wt%, etc.

[0030] In some preferred embodiments, the atomization temperature of the spray powder is 1000–1100°C; the atomization pressure of the spray powder is 10–12 bar; and the atomization rate of the spray powder is 1–3 kg / min.

[0031] In some preferred embodiments, the particle size of the copper-gallium alloy powder is no greater than 60 mesh.

[0032] In some preferred embodiments, the method further includes: annealing the copper-gallium target material; preferably, the annealing temperature is 300~400℃, such as 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, etc.; the annealing time is 2~3h, such as 2h, 2.2h, 2.5h, 2.8h, 3h, etc.

[0033] The present invention also provides a copper gallium target material, which is prepared by the aforementioned preparation method.

[0034] To facilitate understanding of the present invention, the invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0035] Example 1

[0036] Vacuum casting: High-purity copper blocks and high-purity gallium are placed in a vacuum melting furnace in a certain proportion, with a gallium content of 55wt%, a melting temperature of 800℃, a melting time of 70min, and a vacuum degree of <0.2pa. After melting, the mixture is poured into a mold and cooled.

[0037] Spray powdering: The above copper-gallium alloy ingots are loaded into a spray powdering furnace for spray powdering, wherein the parameters are: atomization temperature of 1050℃, atomization pressure of 10 bar, and atomization rate of 3 kg / min, to obtain copper-gallium alloy powder with a particle size of less than 60 mesh.

[0038] Hot isostatic pressing: The copper gallium powder is packaged in a sleeve and then hot isostatically pressed. The temperature is 600℃, the pressure is 150Mpa, the holding time is 120min, and the temperature is cooled down with the furnace after holding.

[0039] Annealing: After the above process, the cladding is removed, and the copper-gallium alloy target is annealed at 400°C for 3 hours and cooled in the furnace.

[0040] Comparative Example 1

[0041] The only difference between this comparative example and Example 1 is that the melting temperature in the vacuum casting step is different; the melting temperature is 770°C.

[0042] Comparative Example 2

[0043] Vacuum melting-spray powdering: High-purity copper blocks and high-purity gallium are placed in a vacuum melting furnace in a certain proportion, with a gallium content of 55 wt%. The melting temperature is 800℃, the melting time is 55 min, and the vacuum degree is <0.2 Pa to obtain an alloy liquid. The alloy liquid is then sprayed into powder with the following parameters: atomization temperature of 1050℃, atomization pressure of 10 bar, and atomization rate of 3 kg / min.

[0044] Hot isostatic pressing: The copper gallium powder is packaged in a sleeve and then hot isostatically pressed. The temperature is 600℃, the pressure is 150Mpa, the holding time is 120min, and the temperature is cooled down with the furnace after holding.

[0045] Annealing: After the above process, the cladding is removed, and the target is annealed at 400℃ for 3 hours. The target is then cooled down in the furnace to a copper-gallium alloy target. Upon observation, it was found that there was a metallic substance on the surface of the target. After testing, the metallic substance was identified as gallium, indicating that the reaction was incomplete and that component segregation had occurred.

[0046] Example 2

[0047] Vacuum casting: High-purity copper blocks and high-purity gallium are placed in a vacuum melting furnace in a certain proportion, with a gallium content of 35wt%. The melting temperature is 900℃, the melting time is 60min, and the vacuum degree is <0.2pa. After melting, the mixture is poured into a mold and cooled.

[0048] Spray powdering: The above copper-gallium alloy ingots are loaded into a spray powdering furnace for spray powdering, wherein the parameters are: atomization temperature of 1100℃, atomization pressure of 12 bar, and atomization rate of 2 kg / min, to obtain copper-gallium alloy powder with a particle size of less than 60 mesh.

[0049] Hot isostatic pressing (HIP): The copper-gallium powder is packaged in a sleeve and then hot isostatically pressed at 700°C and 180 MPa for 90 minutes. The powder is then cooled in the furnace.

[0050] Annealing: After the above process, the cladding is removed, and the copper-gallium alloy target is annealed at 300°C for 3 hours and cooled in the furnace.

[0051] Example 3

[0052] Vacuum casting: High-purity copper blocks and high-purity gallium are placed in a vacuum melting furnace in a certain proportion, with a gallium content of 45wt%. The melting temperature is 850℃, the melting time is 70min, and the vacuum degree is <0.2pa. After melting, the mixture is poured into a mold and cooled.

[0053] Spray powdering: The above copper-gallium alloy ingots are loaded into a spray powdering furnace for spray powdering, wherein the parameters are: atomization temperature of 1000℃, atomization pressure of 11 bar, and atomization rate of 1 kg / min, to obtain copper-gallium alloy powder with a particle size of less than 60 mesh.

[0054] Hot isostatic pressing (HIP): The copper-gallium powder is packaged in a sleeve and then hot isostatically pressed at 650°C and 160 MPa for 100 min. The powder is then cooled in the furnace.

[0055] Annealing: After the above process, the cladding is removed, and the copper-gallium alloy target is annealed at 350°C for 2 hours and cooled in the furnace.

[0056] The relative density and compositional uniformity of the target materials obtained in each embodiment and comparative example are shown in Table 1.

[0057] Example 4

[0058] The only difference between this embodiment and Embodiment 1 is that the hot isostatic pressing temperature is different; the hot isostatic pressing temperature is 580°C.

[0059] Example 5

[0060] The only difference between this embodiment and Embodiment 1 is that the hot isostatic pressing temperature is different; the hot isostatic pressing temperature is 750°C.

[0061] Example 6

[0062] The only difference between this embodiment and Embodiment 1 is that the hot isostatic pressing time is different; the hot isostatic pressing time is 60 minutes.

[0063] Example 7

[0064] The only difference between this embodiment and Embodiment 1 is that the hot isostatic pressing time is different; the hot isostatic pressing time is 150 minutes.

[0065] As can be seen from Table 1, the target materials prepared in Examples 1-3 have uniform composition and a relative density higher than 98%; the target materials prepared in Comparative Examples 1 and 2 show segregation, and elemental gallium appears on the surface of the target material obtained in Comparative Example 2; the target materials obtained in Examples 4-7 have uniform composition, but the relative density (i.e., density) is reduced.

[0066] Table 1

[0067]

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a copper-gallium target, characterized in that, include: High-purity copper blocks and high-purity gallium are vacuum-melted as raw materials, wherein the gallium content in the raw materials is 35~55 wt.%, and after melting, the mixture is cast into a mold and cooled to obtain a copper-gallium alloy; the temperature of the vacuum melting is 800~900℃. Copper-gallium alloy is spray-dried to obtain copper-gallium alloy powder; the atomization temperature of the spray-dried powder is 1000-1100℃. Copper-gallium alloy powder is subjected to hot isostatic pressing and then cooled to obtain a copper-gallium target material; the hot isostatic pressing temperature is 600-700℃; the hot isostatic pressing holding time is 90-120min.

2. The method for preparing the copper-gallium target as described in claim 1, characterized in that, The pressure of the hot isostatic pressing is 150-200 MPa.

3. The method for preparing the copper-gallium target as described in claim 1, characterized in that, The vacuum degree of the vacuum melting is <0.2 Pa; the vacuum melting time is 60-90 min.

4. The method for preparing the copper-gallium target as described in claim 1, characterized in that, The atomization pressure of the spray powder is 10-12 bar; the atomization rate of the spray powder is 1-3 kg / min.

5. The method for preparing the copper-gallium target as described in claim 1, characterized in that, The particle size of the copper-gallium alloy powder is no greater than 60 mesh.

6. The method for preparing the copper-gallium target as described in any one of claims 1 to 5, characterized in that, Also includes: The step of annealing the copper-gallium target.

7. The method for preparing the copper-gallium target as described in claim 6, characterized in that, The annealing temperature is 300~400℃; the annealing time is 2~3h.

8. A copper-gallium target, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 7.

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